Subject: [mobile-ip] Mobile IPv6 Issue 71 (HA Service Discovery and MN Address Provisioning)

From: [email-masked]
Date: Wed, 18 Sep 2002 16:25:18 -0500

Issue 71: HA Service Discovery and MN Address Provisioning
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http://www.piuha.net/~jarkko/publications/mipv6/issues/issue71.txt

Issue: Mobile IPv6 specifies a Home Agent discovery mechanism as well
as the ability to configure its home address dynamically. These are
specified in sections 6.5, 6.6, 6.7, 6.8, 10.9, 11.3.2, 11.3.3 and
11.3.4
The home agent discovery and address autoconfiguration can be
accomplished via existing mechanisms such as DNS (querying the SRV
records for the HA in its home network) for home agent discovery and
possibly using DHCPv6 for home address assignment. Does the MIPv6
protocol need to incorporate this functionality as part of the base
specification or can these features be worked on as extensions to the
base protocol in a separate draft.

Recommendation:
---------------

1. The home agent discovery mechanism is essential to the base
   protocol for purposes such as:
   a. Load balancing - An HA may reject a binding update from an MN
   because it does not have sufficient resources to serve the MN. The
   MN may need to perform HA discovery to find other HAs in its home
   network. (of course an MN may be configured with the address of
   more than one HA, but this is optional). 
   b. New home agents may be added and existing ones that an MN is
   aware of may be offline (for any number of reasons). In such cases
   the ability to do a dynamic HA discovery is useful.

So instead of pursuing an entirely new mechanism which may take a
while to be standardized, it is better to leave the current HA
discovery mechanism untouched. If DNS based proposals are developed in
the future and implementation experience shows that HA discovery is
not really useful, the feature can be deprecated as part of moving the
protocol to draft standard.

2. The dynamic Home address assignment mechanism via ICMP
   request/response messages (Mobile Prefix
   Solicitation/Advertisement) provide an independent mechanism to
   bootstrap a MN when in a visited network. Relying on DHCPv6 or AAA
   puts dependencies that would make deployment of MIPv6 on a large
   scale rely on existence of DHCP relays or AAA elements etc. 
   
   So lets leave the HoA discovery mechanism in the draft as is.

The size of the draft should not really be a concern since anyone
seriously planning on implementing the spec needs to understand all
the details. 

If you have concerns about the above recommendation, please post your
views to the list.

-Basavaraj

---

From: "James Kempf" <[email-masked]>
Date: Wed, 18 Sep 2002 16:03:39 -0700

Agree.

            jak

----- Original Message -----
From: <[email-masked]>
To: <[email-masked]>
Sent: Wednesday, September 18, 2002 2:25 PM
Subject: [mobile-ip] Mobile IPv6 Issue 71 (HA Service Discovery and MN Address
Provisioning)